The method according to the invention enables a facility having a rather reduced dimension, for incinerating to be used, melting and vitrifying mixed waste (30) introduced into a reactor (10), by means of a basket (18) in turn passing through an air lock (12). Plasma torches (14) burn all waste (30) contained in the basket (18). The waste is then lowered in a melting bath of a furnace (20) with an inductor (24) including a crucible-forming container (23). A combustion gas treatment train completes the facility. The furnace (20) can be dismantled, after a series of treatments of several baskets (18) of waste (30) for disassembling the crucible-forming container (23) from the furnace (20). Application in treating different radiologically contaminated and/or toxic mixed waste.